In 2019 or 2020, NASA will resurrect the NASA railroad when the new deep space "Space Launch System" program is operational. Two shuttle-derived solid fuel rocket boosters will be used at least for the initial flights of the "SLS". Each new booster provides 3.6 million pounds of thrust by adding one additional solid fuel propellant section to modified Space Shuttle boosters (5 sections vs. 4). This "SLS" booster will be the largest most powerful solid propellant booster ever built. The boosters will once again be manufactured by Orbital ATK in Utah and shipped cross country by rail.